Changes in cigarette consumption and intention to quit in response to the COVID-19 pandemic in China

INTRODUCTION Significant changes occurred in the way people socialize and interact with each other since China reported its first COVID-19 cases. However, little is known about how smoking behaviors may have changed due to the COVID-19 pandemic in China. The aim of this study was to assess changes in smoking behavior and intention to quit during the early stage of the COVID-19 pandemic in China and to investigate the associated factors. METHODS An online cross-sectional survey was conducted among Chinese adult smokers. Participants were recruited through snowball sampling from 19 March to 2 April 2020. RESULTS A total of 1388 smokers participated in this study. Of those, 1014 (73.0%) reported not changing their cigarette consumption, 104 (7.5%) reported smoking more and 268 (19.3%) reported smoking less due to the pandemic. Average daily cigarette consumption among all participants decreased from 15.0 (IQR: 10.0–20.0) to 13.0 (IQR: 8.0–20.0) (W=6.919, p<0.001). For intention to quit, 270 (19.5%) respondents reported becoming more willing to quit, and 91 (6.6%) reported becoming less willing to quit. Multivariate analyses showed that tobacco addiction, overall knowledge about the relationship between smoking and COVID-19, level of attention devoted to COVID-19, anxiety, living alone, and number of smokers in the family were significantly correlated with cigarette consumption and intention to quit, and living alone was the strongest factor associated with increased cigarette consumption (AOR=5.29; 95% CI: 1.51–18.56). CONCLUSIONS The COVID-19 pandemic led to a slight decrease in cigarette consumption and an increase in quitting intention among Chinese smokers. During the early stages of the pandemic, it was important to focus on the anxiety of smokers, dispel smokers’ misunderstandings of smoking and COVID-19 and create a supporting environment in the family to help smokers quit.


INTRODUCTION
China was the first country to report cases of SARS-CoV-2 infection, which causes the coronavirus disease 2019 (COVID- 19), in December 2019 1 . Because of the limited knowledge about SARS-CoV-2 and COVID-19 at the early stages of the COVID-19 pandemic and that no COVID-19 vaccines or treatments were available at the time, efforts to control the pandemic focused primarily on restricting the community spread of SARS-CoV-2 in early 2020. Many cities and provinces across China, for example, have implemented measures to restrict the community spread of SARS-CoV-2 since the beginning of 2020 2 . These measures included mandated quarantine for those with SARS-CoV-2 infection, stay-at-home orders, limiting travel except for essential activities, prohibiting crowd gathering, and mask mandates in public places 2,3 .
Smoking prevalence was high (50.5%) among Chinese men before the COVID-19 pandemic 4 . In addition, smoking plays an important role in socialization among some Chinese smokers. The COVID-19 pandemic and the resultant pandemic control measures reduced the opportunities for socialization, which may decrease smoking and cigarette consumption 5 . Furthermore, the knowledge and information about the relationship between smoking and COVID-19 may also influence smoking behaviors. For example, early reports showing smokers may be at higher risk of COVID-19 infection 6 , and many studies demonstrating that smokers were more likely to develop severe cases of COVID-19 than non-smokers, could lead to an increase in smokers' motivation to quit smoking and a reduction in cigarette consumption among those who continue to smoke 7,8 .
However, the COVID-19 pandemic and the resultant pandemic control measures in China may also lead to changes that potentially increase smoking and cigarette consumption. A meta-analysis found that individuals experienced higher rates of depression (45%, 95% CI: 37-54) and anxiety (47%, 95% CI: 37-57) during the COVID-19 pandemic 9 . Smoking is often used as a coping mechanism for dealing with anxiety and depression; as such, smoking and cigarette consumption could potentially increase due to higher levels of anxiety and depression during the pandemic 10 . In addition, misinformation about the relationship between smoking and COVID-19, such as 'smoking can prevent SARS-CoV-2 infection' or 'cigarette smoke can kill SARS-CoV-2', may increase daily cigarette consumption among smokers who believe such misinformation 11,12 . Consequently, the overall impact of the COVID-19 pandemic and the resultant pandemic control measures on smoking and cigarette consumption may be mixed, and empirical evidence is needed to assess such an impact. Unfortunately, research that examines how the COVID-19 pandemic affects smoking in China is limited.
Identifying the overall influence of the early stage of the pandemic on smoking behaviors has both theoretical and practical significance for tobacco control in China. Previous studies using the data in the United States and Europe reported mixed effects of the pandemic on smoking behaviors in the early stage of the COVID-19 pandemic 13 . For example, a few studies reported increased interest in quitting and reduction in smoking among smokers in response to the pandemic 14 . However, other studies reported increased smoking rates and decreased quit attempts among smokers 15,16 . The number of studies examining the changes in smoking behaviors in response to the pandemic, specifically for Chinese smokers, is limited 17,18 . One study conducted in China in October 2020 found that more individuals chose to quit smoking and reduced the number of cigarettes they consumed daily after the outbreak of the pandemic 17 . By contrast, a second study conducted in May 2020 found no changes in cigarette consumption after the outbreak of COVID-19 in China. However, this study did not examine the factors associated with cigarette consumption 18 .
Our study aims to address this critical gap in the literature by assessing the changes in smoking behaviors and intention to quit among Chinese smokers early in the pandemic and identifying the factors associated with such changes. The findings from our study could provide insight into smokingrelated behaviors during the pandemic in China and may help inform the design of educational campaigns and policies aimed at reducing tobacco use among Chinese smokers during the pandemic.

Design and participants
This cross-sectional online survey was conducted using the Wenjuanxing platform (a popular online survey platform in China) from 19 March to 2 April 2020 (14 days). The inclusion criteria were: 1) aged >18 years; 2) smoked at least 100 cigarettes in their lifetime; and 3) smoked more than one cigarette in the month before the survey. Participants were recruited using snowball sampling via WeChat, the largest and most-used social media platform in China. The recruitment link was posted on WeChat with public access using the research team members' 'Friends Circle', a function similar to posting public posts on Twitter and Facebook, which can be used to share personal photos or public website links in one's 'Moments (or Timeline)' and make them visible to friends on the platform. The recruitment link could be further shared by anyone who saw the link in their respective 'Friends Circle', achieving additional snowball samples. Written consent was obtained from the eligible participants before they participated in the survey. The online survey included questions on demographics, cigarette consumption, intention to quit, quitting attempts, and two quality control questions. On average, it took participants approximately 5 minutes to complete the survey. In total, 1709 respondents from 31 provinces and autonomous regions in China participated in the online survey. After removing the invalid responses (e.g. excluding those who reported themselves as nonsmokers in the survey and completed the survey in <2 minutes), 1388 (81.2%) participants were included in the current study.

Cigarette consumption
Changes in cigarette consumption were measured using the self-reported question: 'Has your cigarette consumption changed since the COVID-19 outbreak?'. The response categories included: 1) smoking more, 2) smoking less, 3) having quit after the COVID-19 outbreak, 4) relapsed after the COVID-19 outbreak, and 5) no change. We categorized the answers into three categories: smoking more than before (including smoking more and relapsed), smoking less than before (including smoking less and quitting), and no change in smoking. Daily cigarette consumption before and after the outbreak of COVID-19 was measured by the following questions: 'How many cigarettes did you smoke per day on average before the pandemic?' and 'How many cigarettes did you smoke per day on average after the pandemic?'. For those who reported decreasing or increasing cigarette consumption, two additional probing questions were asked about the reasons for decreasing/increasing their cigarette consumption after the pandemic.

Intention to quit and quit attempts
The following two questions measured the intention to quit. The first was: 'Has your interest in quitting smoking changed recently because of the COVID-19 outbreak?'. Response categories included: 1) Yes, intention changed, 2) No change, still want to quit, and 3) No change, still not willing to quit. For the respondents who confirmed their change in quitting intention, a follow-up question was asked: 'How has your intention to quit smoking changed as a result of the pandemic?'. Response categories were: 1) Did not want to quit smoking before, but now want to quit; 2) Wanted to quit smoking before, but no longer want to quit now; 3) Wanted to quit smoking before but the intention has decreased; and 4) Wanted to quit before and the intention has increased. Based on the responses to these two questions, the change in intention to quit was constructed with three categories as follows: 1) Intention to quit increased (did not want to quit smoking before, but now want to quit; wanted to quit before and the intention has increased); 2) Intention to quit decreased (wanted to quit smoking before, but no longer want to quit now; wanted to quit smoking before but the intention has decreased); and 3) Intention not changed.
Quitting attempts during the COVID-19 pandemic were assessed for those who made any quit attempts since the outbreak began, using the following two questions: 1) 'How many times did you abstain from smoking for more than 24 hours during the pandemic?', and 2) 'What was the maximum duration (in days) of your abstinence since the outbreak began'.

Covariates
Knowledge about the relationship between smoking and COVID-19 was measured by four questions. The participants were asked about their opinions about the accuracy of four statements that were widely seen on Chinese social media in the early stage of COVID-19 in China. The response categories for each statement included 'correct', 'incorrect', and 'not sure' 11 4 between smoking and COVID-19 was constructed based on the responses to these four statements. This variable was coded into two categories: 1) at least one item was incorrect, and 2) all four items were correct.
Anxiety was assessed using the Chinese version of the Generalized Anxiety Disorder Scale (GAD-7), which assesses anxiety based on the Diagnostic and Statistical Manual of Mental Disorders (5th ed.) 19 . The reliability and validity of the Chinese version of the GAD-7 have been well-established by previous research 20 . There are seven items in the GAD-7, and the maximum score is 21. Anxiety was categorized as normal, mild anxiety, moderate anxiety and severe anxiety using the cutoff points of 5, 10, and 15, respectively 15 .
The following covariates were also included in this study: biological sex, age, education level (middle school and below, high school degree, associate degree, Bachelor's degree and higher), and selfperceived severity of local COVID-19 epidemic. The last was assessed by the following question: 'How do you think the severity of the COVID-19 epidemic in your city/locality compared with the overall situation in the country?' with response categories 'worse than average', 'similar to the average', and 'better than average'. Other covariates were the number of smokers in family (1 or >1), tobacco addiction (assessed using the heaviness of smoking index, HSI, with cutoff point of 4) 21 , amount of attention devoted to COVID-19 (measured by the question: 'In the past month, to what extent did you pay attention to the COVID-19 related information?' with response categories 'high attention', 'moderate attention', and 'low attention'), perceived self-risk of COVID-19 infection (measured by the question: 'How likely do you think you will become infected with COVID-19?', with response categories 'very likely', 'somewhat likely', 'not likely'), living with children (yes, no), and living alone (yes, no).

Statistical analysis
Frequencies and proportions were computed for the changes in cigarette consumption and quitting intention, reasons for cigarette consumption changes, and the demographic characteristics. Median and interquartile ranges (IQR) were computed for daily cigarette consumption and the duration of abstinence. The kappa identity test was used to examine the consistency between daily cigarette consumption and self-reported changes in cigarette consumption. The related-samples Wilcoxon test was applied to examine the difference between participants' daily cigarette consumption before and after COVID-19. Due to the failure to meet the requirements of the proportional odds assumption (p<0.001), the ordinary logistic regression model was not appropriate for the data. We used multinomial logistic regression to identify potential factors related to cigarette consumption and intention to quit. Adjusted odds ratios (AORs) and their 95% confidence intervals (CIs) were used to quantify the effects. Sex, age, education level, living with children, living alone, number of smokers in the family, tobacco addiction, overall knowledge, amount of attention devoted to COVID-19, perceived self-risk of COVID-19, anxiety, and local COVID-19 situation, were controlled for in all models. SPSS software version 20.0 (SPSS, Chicago, IL, USA) was used to conduct analyses. All tests were two-sided, and p<0.05 was considered statistically significant.

Demographic characteristics
Among the 1388 respondents, 1329 were males (95.7%), and 59 were females (4.3%), with an average age of 43.9 ± 12.0 years. One-third (33.2%) of the participants had a Bachelor's degree and higher, and more than half of the participants (58.2%) lived in cities. Only 77 (5.5%) respondents felt that the COVID-19 situation in their local community was more severe than the overall situation in the country. Most participants (66.1%) had no other smokers living with them, and 85.1% of participants reported a low level of addiction to tobacco (Table 1).

Cigarette consumption
Among the 1388 respondents in this study, 104 (7.5%) reported smoking more after the COVID-19 pandemic (including 30 who relapsed after the pandemic), and 268 (19.3%) reported smoking less than after the COVID-19 pandemic (including 72 who had quit due to the COVID-19 pandemic).   a Only asked among smokers who reported smoking more than before. b Only asked among smokers who reported smoking less than before. cigarette consumption and self-reported changes in cigarette consumption (p<0.001). Reasons for changes in cigarette consumption are listed in Table 2.

Intention to quit and quitting attempts
In all, 270 (19.5%) respondents reported becoming more willing to quit, and 91 (6.6%) respondents reported becoming less willing to quit, since the start of the COVID-19 pandemic in China. A total of 208 (15.0%) respondents reported they had tried to stop smoking for more than 24 hours during the COVID-19 pandemic. The maximum duration of abstinence among those who reported having made quit attempts ranged from 1 day to 60 days (median=5.0, IQR: 2.0-15.0).

DISCUSSION
This is one of the first studies to evaluate the change in cigarette consumption and quitting intention in the early stages of the COVID-19 pandemic across China. Our study found that, in general, Chinese smokers decreased smoking consumption and increased quitting intention during the early pandemic. The study also indicated that knowledge about smoking and COVID-19, attention to the pandemic, perceived self-risk, the local status of epidemic control and the number of smokers in the family were associated with such change. All of the above findings provide practical evidence for tobacco control-related education during the COVID-19 pandemic, which could be a 'learnable window' to encourage smokers to quit 22 .
Unlike the study of Liao et al. 18 in May 2020, which found no changes in cigarette consumption after the outbreak of COVID-19 in China, the present study showed a significant decrease in daily cigarette consumption among smokers after the outbreak of COVID-19. The difference between the two studies maybe attributed to the gap in knowledge about the relationship between smoking and COVID-19. Our study proved that more knowledge about the relationship between smoking and COVID-19 was associated with the decrease in cigarette consumption. In the study of Liao et al. 18 , only 26.2% of current smokers agreed that smoking was a risk-factor for COVID-19 infection. However, this study indicated that 58.1% of participants disagreed that smoking can prevent COVID-19.
Family plays an important role in smoking behavior. This study found that living alone was a strong factor associated with more cigarette consumption and less quitting intention. This might be because smokers who live alone may smoke more due to boredom as there is lower communication with others. Also, they are less likely to receive complaints from family members during the stages of stay-at-home restrictions 11,23 . This is consistent with self-reports of participants that family members' persuasion was an important reason for decreased cigarette consumption. However, the multivariate regression implied that when there were other smokers in family, participants were less likely to reduce cigarette consumption. Therefore, family members should encourage smokers to quit and create supportive environments to help them to stop smoking. Community health workers should pay more attention to smokers who live alone.
Our findings also indicate that more attention to the COVID-19 pandemic could help decrease cigarette consumption and enhance quitting intention, which is consistent with previous studies 14, 24 . This is possible because high levels of COVID-19 attention could result in more related news seeking, from which smokers may improve their understanding of the risk of smoking and the importance of cessation during the pandemic [25][26][27][28] . Thus, media should take the role of informing the public about the risk of smoking during the pandemic.
However, some misunderstandings spread by the media about the relationship between smoking and COVID-19 may reduce one's intention to quit, such as 'Nicotine may be a treatment option for COVID-19' and 'Smoking can prevent COVID-19' 11,12,29,30 . These incorrect views mostly came from rumors spread by social media among smokers and have become part of smoking rationalization beliefs, which catered to smokers' needs and helped them feel at ease while smoking [31][32][33] . As a result, smokers rationalize their smoking behaviors and are less likely to intend to quit 34 . It is the responsibility of the public health departments and the media to be good 'gatekeepers' and clarify the misunderstandings and rumors that have spread among smokers and have become smoking cessation barriers.
Among those related factors, anxiety was special because it could both enhance and decrease cigarette consumption. Previous studies indicated that anxiety caused by the changes in social contact, uncertainty about the future, job losses, and economic stress under the background of COVID-19 was positively associated with increased cigarette consumption 15,34,35 . Moreover, the present study also demonstrated that anxiety might decrease one's cigarette consumption and motivate the intention to quit. We speculate that this anxiety was mainly caused by the focus on health. Such health-focused anxiety was common among current smokers because they had to face more severe consequences than non-smokers if infected with COVID-19 7 . Previous findings confirmed that health-focused anxiety might lead to increased quitting willingness 36 . Although anxiety may help to quit smoking, we discourage the media over emphasizing the consequence of COVID-19 infection among smokers, to avoid arousing severe anxiety. Besides, psychological institutions should also provide counselling services to help the public, including smokers, to develop a correct understanding of anxiety during the COVID-19 pandemic.

Limitations
There are still a few limitations in this study. First, as a cross-sectional study, smoking intention and consumption before and during the COVID-19 pandemic were self-reported, resulting in recall bias. Second, the online survey may lead to selection bias, and the sample of this study was predominantly males with low tobacco addiction and better local COVID-19 control situations. Compared to more than 300 million smokers in China, the sample size of this study is really small. Thus, the sample may not be representative of the smoking population in China. Third, our study relied exclusively on selfreported data without biochemical verification. Further research may use longitudinal approaches and direct observation to explore additional evidence of the impact of the pandemic on smoking and other health-related behaviors.

CONCLUSIONS
Our study found positive changes in cigarette consumption and quitting intention in response to the early stage of the COVID-19 pandemic in China. We believe that the reduction in cigarette consumption was associated with public attention to COVID-19 and perceived self-risk to infection. Knowledge about the relationship between smoking and COVID-19, as well as anxiety, may be related to intention to quit. It is essential for the media to inform the public about the risk of smoking and dispel related misunderstandings. Psychological institutions should provide counselling services to relieve the anxiety of smokers, and family members should encourage smokers to quit.